Robert Boschgmbh

Rainer Noack

Helmut Weyl

Wolfgang Heinemann

Ernst Linder

Karl-Hermann Friese

Helmut Maurer

Leo Steinke

Lothar Weber

Willi Frank

Jurgen Treiber

Hans-Ulrich Gruber

Hermann Fischer

Klaus-Dieter Pohl

Hans Hurbert

Volker Brendick

Gunter Knoll

Method for producing electrodes for spark plugs and spark plug electrodes

To manufacture a vibration-resistant, shock-resistant electrical connection on a ceramic substrate (11) having an electrically conductive layer (12) applied to a surface (13, 19) thereof, a groove or channel-like depression (16, 20) is formed in the surface, preferably also including a through-bore (18), into which a conductor (17) is placed. The space between the conductor and the groove, the through-bore, if provided, and an extending groove at the other surface (19) of the substrate is filled with a sinterable mass (21), preferably a cermet, containing a metal which is compatible with the metal of the conductor wire (17), both for example containing platinum. As a starting material, the plate with the grooves therein is extrusion-pressed, pre-sintered at a low temperature to give it form stability, then the electrode (12) is applied, then the electrical conductor (17) and the cermet is applied and then the entire sub-assembly is fired to sintering temperature, e.g. about 1500.degree. C.; if desired, a further protective coating (22) of magnesium spinel may be plasma-sprayed on. Due to shrinkage of the ceramic components, the wire (17) will be securely held in position in the groove, and the cermet additionally forming an electrical connection between the wire and the substrate (11). For additional strain relief, the groove can be undulating (FIG. 3).

Method of making a vibration-resistant electrical component and

To improve operation and output voltage, particularly at 400.degree. C. and less, an oxygen sensor, especially adapted to determine oxygen content of automotive exhaust gases, is constructed by utilizing two electrodes applied on a body of stabilized zirconium dioxide, for example a closed tube, by making an electrode exposed to the exhaust gases in form of a mixture of finely dispersed ceramic material and a platinum-rhodium alloy, the ceramic material being present at about 40% (by volume) and 60% (by volume) platinum-rhodium alloy of 50-94% platinum and 50-6% rhodium (by weight). The second electrode, exposed to a reference gas comprises an alloy of palladium and another noble metal in a ratio of about 19-90% (by weight) Pd and 81-10% (by weight) noble metal. This electrode may also contain up to 40% (by volume) finely dispersed ceramic material. The electrode exposed to the exhaust gases is covered with a porous coating. The electrodes can be applied as aqueous or organic solutions of soluble noble metal compounds or suspensions, colloidal suspensions, with organic solvents, and the like, and subsequent sintering.

Oxygen content exhaust gas sensor, and method of its manufacture

Growing community of inventors

Markgroningen, Germany

Rainer Noack